CN103185956B

CN103185956B - Miniature projection lens

Info

Publication number: CN103185956B
Application number: CN201210118943.5A
Authority: CN
Inventors: 黄郁湘; 熊坚智; 林昀毅
Original assignee: Asia Optical Co Inc
Current assignee: Asia Optical Co Inc
Priority date: 2011-12-27
Filing date: 2012-04-20
Publication date: 2015-07-08
Anticipated expiration: 2032-04-20
Also published as: US20130163097A1; US8953259B2; CN103185956A; TWI443407B; TW201326955A

Abstract

The invention relates to a micro projection lens, which comprises a first lens, an aperture, a second lens, a third lens and a fourth lens which are arranged in sequence from an imaging side to an image source side along an optical axis, wherein the first lens is a crescent lens with positive refractive power, the convex surface of the crescent lens faces the imaging side, and at least one surface of the crescent lens is an aspheric surface; the second lens is a biconcave lens with negative refractive power, and at least one surface of the second lens is an aspheric surface; the third lens is a biconvex lens with positive refractive power; the fourth lens is a biconvex lens with positive refractive power, and at least one surface of the fourth lens is an aspheric surface.

Description

Miniature projection lens

Technical field

The present invention is relevant with camera lens, in more detail refers to a kind of Miniature projection lens.

Background technology

In recent years, along with the progress of image science and technology, utilize projector to carry out bulletin, video signal, meeting or the people of ornamental film and get more and more.And carry and use for making projection function be more convenient for, its in order to by image definition be presented on the projection lens on screen volume also will be reduced significantly, to meet desired miniaturization and light-weighted demand, moreover, except miniaturization and lightweight, also want to have higher optical performance, the image reaching high resolving power and high contrast just can be made to represent.Therefore, miniaturization and high optical performance are indispensable two important documents of projection lens.

But the camera lens that current projector adopts, for reaching the object of high optical performance, nothing more than the mirror group employing many groups, even has eyeglass to sum up more than more than ten persons.In addition, also promisingly reach the object making Miniature projection lens lightweight and miniaturization, and only use several pieces eyeglasses, but make its optical performance effectively to promote.

Comprehensive the above, known Miniature projection lens is not attained perfect yet, and the part that still haves much room for improvement.

Summary of the invention

The technical problem to be solved in the present invention is, cannot take into account the defect of miniaturization and high optical performance for projection lens of the prior art, provides a kind of Miniature projection lens, and not only volume is little and have high optical performance.

The technical scheme that the present invention adopts for its technical matters of solution is, a kind of Miniature projection lens is provided, to include along optical axis and by becoming the first eyeglass of image side to image source side sequential, aperture, the second eyeglass, the 3rd eyeglass and the 4th eyeglass, wherein, this first eyeglass is the meniscus lens with positive refractive power, it is convex surface facing this one-tenth image side, and at least one surface is non-spherical surface; This second eyeglass is the biconcave lens with negative refractive power, and at least one surface is non-spherical surface; 3rd eyeglass is the biconvex lens with positive refractive power; 4th eyeglass is the biconvex lens with positive refractive power, and at least one surface is non-spherical surface.

According to above-mentioned design, this Miniature projection lens more meets following condition:

42mm＜f1＜52mm；

-4.8mm＜f2＜-4.3mm；

7mm＜f3＜7.8mm；

9mm＜f4＜10mm；

Wherein, f1 is the effective focal length of the first eyeglass, the f2 effective focal length that is the second eyeglass, the f3 effective focal length that is the 3rd eyeglass, f4 be the effective focal length of the 4th eyeglass.

By this, by above-mentioned design, not only volume little and have high optical performance simultaneously will to make this Miniature projection lens.

Accompanying drawing explanation

Fig. 1 is the eyeglass arrangement plan of present pre-ferred embodiments;

Fig. 2 A is the curvature of field (Field Curvature) figure of present pre-ferred embodiments;

Fig. 2 B is distortion (Distortion) figure of present pre-ferred embodiments;

Fig. 2 C is the out of focus modulation transfer function figure (Through FocusMTF) of present pre-ferred embodiments;

Fig. 2 D is the Space Frequency Modulation transport function figure (SpatialFrequency MTF) of present pre-ferred embodiments;

Fig. 2 E is lateral chromatic aberration (Lateral color) figure of present pre-ferred embodiments.

Embodiment

For can the present invention be illustrated more clearly in, hereby lifts preferred embodiment and coordinate accompanying drawing to be described in detail as follows.

Refer to Fig. 1, the Miniature projection lens of present pre-ferred embodiments includes along optical axis Z and by becoming the first eyeglass L1, the aperture ST of image side to image source side sequential, the second eyeglass L2, the 3rd eyeglass L3 and the 4th eyeglass L4.In addition, inner full-reflection prism TP (Total internal reflection Prism) and glass covering CG (Cover Glass) is more sequentially provided with between 4th eyeglass L4 to image source side, its function belongs to prior art, repeats no more in this appearance.Wherein:

This first eyeglass L1 is made by plastic material and has the meniscus lens of positive refractive power, and its convex surface S1 is towards one-tenth image side, and two surperficial S1, S2 are all non-spherical surface.

This second eyeglass L2 is made by plastic material and has the biconcave lens of negative refractive power, and two surperficial S4, S5 are all non-spherical surface.

3rd eyeglass L3 is made by glass material and has the biconvex lens of positive refractive power, and two surperficial S6, S7 are spherical face.

4th eyeglass L4 is made by plastic material and has the biconvex lens of positive refractive power, and two surperficial S8, S9 are all non-spherical surface.

In addition, this Miniature projection lens is reach to improve image quality, strengthening imaging capability, reduce aberration and reduce the object of the curvature of field and amount of distortion, and more satisfied have following condition:

(1)42mm＜f1＜52mm；

(2)-4.8mm＜f2＜-4.3mm；

(3)7mm＜f3＜7.8mm；

(4)9mm＜f4＜10mm；

Wherein, f1 is the effective focal length of the first eyeglass L1, the f2 effective focal length that is the second eyeglass L2, the f3 effective focal length that is the 3rd eyeglass L3, f4 be the effective focal length of the 4th eyeglass L4.

For reaching above-mentioned purpose and effective optical performance promoting this Miniature projection lens, focal length F (Focus Length), the numerical aperture FNO (F-number) of the Miniature projection lens of present pre-ferred embodiments, radius-of-curvature (radius of curvature), the refractive index Nd (refractive index) of the spacing of the thickness of each eyeglass, each eyeglass, each eyeglass and the Abbe number Vd (Abbe number) of each eyeglass of the optical axis Z of each lens surface by locating, as shown in Table 1:

Table one

In each eyeglass of the present embodiment, the surface indentation degree z of these non-spherical surfaces S1, S2, S4, S5, S8 and S9 obtained by following formula:

z = \frac{{ch}^{2}}{1 + {[1 - (k + 1) c^{2} h^{2}]}^{\frac{1}{2}}} + {Ah}^{4} + {Bh}^{6} + {Ch}^{8} + {Dh}^{10} + {Eh}^{12} + {Fh}^{14} + {Gh}^{16}

Wherein:

Z: the depression degree of non-spherical surface;

C: the inverse of radius-of-curvature;

H: the aperture radius on surface;

K: circular cone coefficient;

A ~ G: each rank coefficient of the aperture radius h on surface.

In the present embodiment, each rank coefficient A ~ G of the circular cone coefficient k (conic constant) of each non-spherical surface and surface apertures radius h is as shown in Table 2:

Table two

The eyeglass of above and the configuration of aperture, make the Miniature projection lens of the present embodiment not only effectively reduced volume to meet the demand of lightweight device for image, image quality also can reach requirement, this can find out from Fig. 2 A to Fig. 2 E.

From Fig. 2 A, the amount of distortion of the present embodiment is no more than 0.5%; From Fig. 2 B, the curvature of field of the present embodiment is no more than-0.005mm and 0.05mm; From Fig. 2 C, the present embodiment still has good resolution in different field positions; From Fig. 2 D, the present embodiment is the time marquis of 90lp/mm, and modulated optical transfer function values still can maintain more than 50%; From Fig. 2 E, the red R of the present embodiment, blue B are less than a picture element size relative to the lateral chromatic aberration of green G, and the resolution of the Miniature projection lens of obvious the present embodiment is standard compliant.

Comprehensive above can to learn, Miniature projection lens of the present invention not only can effectively reduced volume and while can have high optical performance.

The foregoing is only the better possible embodiments of the present invention, the equivalent structure change that all application instructions of the present invention and claim are done, ought to be included in the scope of the claims of the present invention.

Claims

1. a Miniature projection lens, is characterized in that, includes along optical axis and by becoming image side to image source side sequential:

First eyeglass, for having the meniscus lens of positive refractive power, it is convex surface facing this one-tenth image side, and at least one surface is non-spherical surface;

Aperture;

Second eyeglass, for having the biconcave lens of negative refractive power, and at least one surface is non-spherical surface;

3rd eyeglass, for having the biconvex lens of positive refractive power; And

4th eyeglass, for having the biconvex lens of positive refractive power, and at least one surface is non-spherical surface;

This Miniature projection lens more meets following condition: 9mm<f4<10mm, and wherein, f4 is the effective focal length of the 4th eyeglass.

2. Miniature projection lens as claimed in claim 1, it is characterized in that, two surfaces of this first eyeglass are all non-spherical surface.

3. Miniature projection lens as claimed in claim 1, it is characterized in that, two surfaces of this second eyeglass are all non-spherical surface.

4. Miniature projection lens as claimed in claim 1, it is characterized in that, two surfaces of the 4th eyeglass are all non-spherical surface.

5. Miniature projection lens as claimed in claim 1, is characterized in that, more meet following condition:

42mm<f1<52mm, wherein, f1 is the effective focal length of the first eyeglass.

6. Miniature projection lens as claimed in claim 1, is characterized in that, more meet following condition:

-4.8mm<f2<-4.3mm, wherein, f2 is the effective focal length of the second eyeglass.

7. Miniature projection lens as claimed in claim 1, is characterized in that, more meet following condition:

7mm<f3<7.8mm, wherein, f3 is the effective focal length of the 3rd eyeglass.

8. Miniature projection lens as claimed in claim 1, it is characterized in that, this first eyeglass, this second eyeglass and the 4th eyeglass are made with plastic material; 3rd eyeglass is made with glass material.